(CNN) -- A group of U.S. students touring China are gaining an experience they had not expected -- a second round in quarantine following a positive test of the H1N1 flu virus, a chaperone for the group said.

By the time they leave China, the students from Oregon will have spent less than four days actually seeing the country in what had been planned as a three-week tour of the country, said Scott Dewing, one of the chaperones and director of technology at St. Mary's School in Medford, Oregon.

Speaking over the Internet, Dewing said he and his group of 64 students and six more chaperones were keeping their sense of humor. "The forecast here from Dengfeng is a high chance of smog," he said from their hotel.

The students had just been released last Thursday, after spending a week at a Beijing hotel in quarantine over H1N1 fears. The group joined other U.S. students and a group of British children who were quarantined in China's capital following positive H1N1 tests from each of the groups.

After being released, the Oregon group traveled by bus to the city of Dengfeng, Dewing said. Initial roadside tests on Sunday for the H1N1 virus were negative, but results later in the day confirmed a positive test. That student has been placed in a hospital for H1N1 cases, Dewing said. Watch Oregon students released from the first quarantine in Beijing »

By Monday, two more students had tested positive for H1N1, Dewing said, and yet two more on Tuesday reported elevated temperatures.

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Since May, China has been checking people arriving from countries where cases of H1N1 -- also known as swine flu -- have been reported. Anyone with a fever or exhibiting flu-like symptoms has been placed in quarantine, usually in a hospital, while anyone who sat near someone with such symptoms has been sequestered in hotel rooms, the U.S. State Department has said.

"Since we had been through this before, we knew what this meant," Dewing said. "This means another seven-day wait."

The Oregon group -- ranging in age from 14 to 18 -- might now miss its return flight to the United States, Dewing said.

Dewing relayed a conversation he had with one of the students during the first quarantine. "I came here to get an experience," Dewing said the student told him. "This isn't the experience I planned for, but it's an experience, nonetheless."